84 ESSAYS OF A BIOLOGIST 



space and time, so tools represent, biologically 

 speaking, an extension of himself as an operator. 

 While man is using a tool, he and the tool together 

 constitute but a single unit in the struggle for exist- 

 ence. As various writers have put it, tools and 

 machines are temporary organs of man, which have 

 the additional merit of being replaceable if lost or 

 damaged. 



But this is not all : the great power of association 

 possessed by man, together with his faculty of gen- 

 eralization and of speech, makes it possible for him 

 to learn his role in the community, instead of being 

 born with it as are the bee and the ant. Great edu- 

 cability instead of differentiated instinct, infinite 

 possibility, at the expense of the pains of learning, 

 instead of an effortless but limited stock of inborn 

 modes of behaviour — in this again man represents a 

 qualitatively new organic type. 



By this means he can escape what has always been 

 a necessity with lower forms: by means of education 

 and machinery he can play a specialized part in the 

 community life, and so build up a community with 

 a high degree of division of labour, without being 

 born specialized. He could not thus learn his role if 

 he were not educable, nor if he could not manufac- 

 ture tools. An ant or a duck or a dog possesses ad- 

 mirable tools for its particular job: but they are 

 living parts of the organism's own body. A worker 

 ant cannot lay down its serviceable carpentering 

 mandibles and become a soldier by picking up a 



